Save-Point

calibre is a free and open source e-book library management application
developed by users of e-books for users of e-books.
It has a cornucopia of features divided into the following
main categories:

• Library Management
  
• E-book conversion
  
• Syncing to e-book reader devices
  
• Downloading news from the web and converting it into e-book form
  
• Comprehensive e-book viewer
  
• Content server for online access to your book collection
  
• E-book editor for the major e-book formats

hah, no credit to me for telling you about it, I see how it is. Take all the credit.

Also, Calibre supports a wide variety of formats, you should probably note those

Supported formats include CBZ, CBR, CBC, CHM, DJVU, EPUB, FictionBook,
HTML, HTMLZ, LIT, LRF, Mobipocket, ODT, PDF, PRC, PDB, PML, RB, RTF,
SNB, TCR, TXT and TXTZ.


I highlighted a format that many users here will find interesting.